That's pretty clearly not the case; the so-called "interstate commerce clause" in Article I, Section 8 is perhaps more accurately the "interstate and foreign commerce clause", and expressly gives Congress the same authority to regulate trade among the states as it does for foreign trade and trade with Indian tribes; it clearly was not intended to be limited to preventing states from erecting protectionist trade barriers (which, in any case, is the focus of the Article I, Section 10, limits on states.)

> It took the 18th Amendment to prohibit "the manufacture, sale, or transportation of intoxicating liquors...for beverage purposes" at a federal level in 1920. The Volstead Act was able to use that amendment as the basis for its authority.

The Volstead Act went into effect in 1919, the 18th Amendment was ratified in 1920, and went into effect in 1921. Its clear that Congress -- which proposed the 18th Amendment before passing the Volstead Act, which it did over a Presidential veto -- did not believe that the Amendment was necessary to support the act, though they clearly thought it was desirable (perhaps because it didn't just authorize regulation, it explicitly mandated prohibition.)